EP2383490A1 - Uncoupling pulley - Google Patents

Abstract

The pulley has a rim with a driving stop i.e. stop-pin (42), having a face (47) cooperating with an end region (12) of a torsion spring e.g. conical or helical spring, to drive the spring along a closing up direction in a direction of relative rotation of the rim and a bell (3). The bell includes a bell stop (37) whose angular position defines a given maximum value for the travel of the end region of the spring driven in the closing up direction by the driving stop. A cylindrical shaped annular support part i.e. ring, is centered on the bell.

Description

The present invention relates to a decoupling pulley for use in a belt transmission system for attenuating belt tension variations by deforming an elastic component interposed between a driving portion which provides mechanical energy and a portion conducted.

In the case for example of an alternator pulley, the rim of the pulley (driving part) is driven by the belt and the hub of the pulley which is integral with the alternator (driven part). The elastic filter function (low-pass filter) is generally provided by an elastomer body.

For highly acyclic transmission systems (large motor irregularities) or for systems whose cycle of use is very demanding (alternator-starter for example), the vibratory phenomena are such that the rubber filtering body does not allow to ensure a satisfactory compromise between service life and performance in filtering. Indeed, in order to filter properly, the torsional stiffness of the elastomer body must be low while at the same time, the elastomer body must not be too deformed if one wishes to increase its life. As a result, very limited lives are often achieved with average filtering performance.

Decoupling pulleys are known whose elastic stiffness required for filtering is provided by a torsion spring. Decoupling pulleys for automobile accessories (alternator) are described in particular in the Patent Applications US 2006/264280 , US 2008/108442 and WO 2009/47816 .

These pulleys provide a coupling and a decoupling of the spring by a friction system which makes it necessary to work the spring in opening, and which obligatorily impose the implementation of a decoupled mode of operation incompatible with certain applications, in particular the pulleys. alternator-starter (ADS).

The friction coupling / decoupling system is a source of friction and therefore of wear, which affects the stability of performance over time, as well as the reliability and longevity of the product.

Similarly, it is unfavorable to work a spring alternately opening and closing to ensure coupling and decoupling, namely a clutch and a clutch.

The present invention proposes to avoid these disadvantages by eliminating any friction coupling / decoupling system and providing a kinematics that make the spring work only closing.

The invention thus relates to a decoupling pulley comprising a rim integral with a first power transmission element, and a torsion spring mounted in a receptacle integral with a second power transmission element, one of the elements the power transmitting element being driven, characterized in that the receptacle is a bell inside which is centered the spring which has a first and a second end region of which each rests on a support face of the bell, in that the rim has at least one first drive stop having a first face cooperating with the first end region of the spring to drive the latter in the direction closing in a first direction of relative rotation between the rim and the bell, and in that the bell comprises at least one first stop of the bell whose position angular defines a given first maximum value α ₁ for the travel of the first end region of the spring driven to closure by said first drive stop.

A torsion spring is a spring having a plurality of coils wound with an axial pitch (for example a helical or conical spring).

According to a first variant, the pulley can be characterized in that only said first end region cooperates with said first face of said first drive stop, so that the second end region of the spring remains in abutment on its face. support.

It can then be characterized in that, for the second direction of relative rotation between the rim and the bell opposite to said first direction of rotation, the periphery of the bell has an angular sector of free rotation for the first drive stop on a angular deflection α ₄ between the first end of the spring to a second stop of the bell.

Preferably, the second spring end region is disengaged from the angular sector to allow the passage of the first drive stop to said second stopper bell

According to a second variant, the pulley is characterized in that said first end region as well as said second end region cooperate alternately in said relative direction of rotation with said first drive stop for driving the spring to close, and in that the bell has a third bell stop whose angular position defines a second maximum given value α ₂ for the displacement of the second end region of the spring driven to closure by a second face of the first drive stop , opposite the first side.

The bell advantageously has an angular sector α ₃ of constant torque rotation for the first drive stop between the first and the second end of the spring.

An angular sector of constant torque rotation can operate in free rotation or comprise a friction element to exert a braking torque.

According to a third variant, the pulley is characterized in that the spring has a said first end region cooperating with said first face of said first drive stop and a said second end region cooperating with a first face of the second driving abutment for driving the spring in the direction of closure in a second direction of rotation opposite the first direction of rotation, and in that the bell has a said third bell stop whose angular position defines a second maximum value given α ₂ for the travel of the second end region of the spring driven to closure by the second drive stop.

The pulley may be characterized in that the bell has a fourth and a fifth bell stop allowing respectively said angular displacement α ₁ for the second drive stop when the first end of the spring is driven to closure by the first face of the first drive stop and a said angular displacement α ₂ for the first drive stop when the second end of the spring is driven to closure by the first face of the second drive stop.

The angle α ₁ may or may not be equal to the angle α ₂ .

The pulley can be characterized in that at least one said bell stop has a face cooperating with a said face of a said drive stop to define a said given maximum value α ₁ and / or α ₂ , At least one said bell stop face may comprise at least one damping element, for example an elastic element.

The pulley can be characterized in that at least one said stop bell has a face cooperating with a said face of an end region of the spring to define a said given maximum value α ₁ and / or α ₂ .

The pulley may comprise a friction element introducing a contact torque between the first and the second power transmission element.

Said first and / or second end region may be in contact with said support face of the bell.

Alternatively, the pulley may be characterized in that it comprises an annular piece centered on the bell and which has a housing which receives the first end region of the spring, this housing having at least one contact face, which is in contact with the said support face of the bell.

The annular piece may be made of a non-metallic material that attenuates impact noise, such as polyamide or polyurethane, or it may have at least one contact face coated with a shock-absorbing material such as an elastomer or an elastomeric thermoplastic material.

The pulley may be an automobile accessory pulley for example for an alternator in which it is the first power transmission element which is driving, and has a toothing for receiving the toothing of a type K belt and in that the second power transmission element has a coupling element to a said accessory.

The pulley may be a crankshaft pulley in which the second transmission member is driving, the second member having a coupling member to a crankshaft, and the first member having a toothing for receiving the toothing of a type K belt.

The pulley may be an alternator-starter pulley for which the first transmission element may be driving or driven according to the operating mode (starting or started).

• les figures 1a à 1g illustrent une première variante de l'invention dans laquelle une seule butée d'entraînement coopère avec une seule région d'extrémité du ressort, avec deux vues en perspective de la poulie (1a et 1d) ,une vue du ressort (1b), et deux vues de face de la poulie (1c et 1e), les figures 1f et 1g étant des caractéristiques de couple (en N.m) en fonction de l'angle (degrés) ;
• les figures 2a à 2g illustrent une deuxième variante de l'invention dans laquelle une seule butée d'entraînement coopère alternativement avec l'une ou l'autre région d'extrémité du ressort, avec trois vues en perspective de la poulie (2a, 2c, 2d), deux vues de face de la poulie (2b), alors que les figures 2f et 2g sont des caractéristiques de couple (en N.m) en fonction de l'angle (en degrés) ;
• les figures suivantes (3a à 3e ; 4a, 4b ; 5a à 5e) illustrent d'autres variantes de l'invention dans laquelle deux butées d'entraînement coopèrent en alternance avec l'une ou l'autre des deux régions d'extrémité du ressort, à savoir :
• les figures 3a à 3e sont relatives à une poulie d'accessoire, en l'occurrence une poulie d'alternateur, avec un schéma de principe (3a), une vue de la poulie en coupe axiale (3b), une vue en perspective de la poulie avec enlèvement partiel (3c), un éclaté (3d) et un détail en coupe d'une variante permettant l'ajout d'un couple résistant constant ;
• les figures 4a et 4b sont relatives à une poulie de vilebrequin;
• les figures 5a à 5e sont relatives à une poulie d'alterno-démarreur (« ADS ») ;
• les figures 6a à 6e représentent des variantes de ressorts.
• les figures 7a à 7c représentent une variante de l'invention dans laquelle la fonction d'amortissement de bruit est réalisée à l'aide d'une pièce annulaire dans laquelle est logée l'extrémité du ressort qui est sollicité à la fermeture.
• et la figure 8 illustre une variante de réalisation de l'extrémité du ressort lorsqu'elle est logée dans la cloche.

Other features and advantages of the invention will appear better on reading the following description, given by way of non-limiting example, in connection with the drawings in which:

• the Figures 1a to 1g illustrate a first variant of the invention in which a single driving abutment cooperates with a single end region of the spring, with two perspective views of the pulley (1a and 1d), a view of the spring (1b), and two front views of the pulley (1c and 1e), the figures 1f and 1g being torque characteristics (in Nm) as a function of angle (degrees);
• the Figures 2a to 2g illustrate a second variant of the invention in which a single driving abutment cooperates alternately with one or the other end region of the spring, with three perspective views of the pulley (2a, 2c, 2d), two front views of the pulley (2b), while the Figures 2f and 2g are torque characteristics (in Nm) as a function of angle (in degrees);
• the following figures (3a to 3e, 4a, 4b, 5a to 5e) illustrate other variants of the invention in which two drive stops cooperate alternately with one or the other of the two end regions of the invention. spring, namely:
• the Figures 3a to 3e relate to an accessory pulley, in this case an alternator pulley, with a schematic diagram (3a), a view of the pulley in axial section (3b), a perspective view of the pulley with partial removal (3c), an exploded (3d) and a sectional detail of a variant allowing the addition of a constant resistive torque;
• the Figures 4a and 4b relate to a crankshaft pulley;
• the Figures 5a to 5e relate to an alternator-starter pulley ("ADS");
• the Figures 6a to 6e represent variants of springs.
• the Figures 7a to 7c represent a variant of the invention in which the noise damping function is performed using an annular piece in which is housed the end of the spring which is biased to closure.
• and the figure 8 illustrates an alternative embodiment of the end of the spring when it is housed in the bell.

It should be noted that as far as possible, the same reference signs have been kept for the homologous elements of the different variations.

To the Figures 1a to 1d the decoupling pulley comprises a torsion spring (for example a helical or conical spring) 1 ( figure 1b ) comprising, for example, rectangular or circular turns 11. Two curved end regions 12 and 14 ( figure 1b ) allow a drive to close the spring 1 by their face 17, 17 'which is adjacent to the outer edge 15 of the turns 11. The other face 18, 18' which is adjacent to the inner edge 16 of the turns 11, which would serve to to drive the spring 11 in the direction of opening are not used in the context of the present invention to drive the spring 1, but can serve as a stop to limit the angular movement of the spring 1 caused to close.

The spring 1 is centered inside a bell 3 wherein its end regions 12 and 14 are in contact with bell 32 stops ₂ and 34. The end region 12 has an end 19 which protrudes radially the outer cylindrical contour 31 of the bell 3 to allow a drive to close the spring 1 by the face 17. The end region 14, by cons, does not exceed (or virtually no) radially outer cylindrical contour 31 of the bell 3.

A cylindrical region 2 of the bell 3 makes it possible to axially mount the bell 3 on the hub 5 in force.

Two bearings 101 and 102 ensure the relative rotation and the axial retention of the rim 4 and the hub 5. The rim 4 may have an extension cylindrical 6 having a pulley toothing 61 for receiving a grooved belt (automotive belt type K)

The centering of the spring 1, by its outer edge 15, in the bell 3 can be effected directly by the internal contour 33 of the bell 3, or as represented by a split centering ring 36 (ends 36 ₁ and 36 ₂ ). which is visible also in the exploded view of the figure 5d . It is arranged between the spring 1 and the bell 3 to facilitate the mounting of the spring.

The face 17 is in contact with the abutment 32 ₂ and the face 17 'is in contact with the abutment 34, these two abutments being spaced angularly by an angle which preferably allows a slight pre-stress (for example of the order of 1 ° to 5 °) of the spring 1 in the direction of closure, which allows the spring never to go through its position empty and not preloaded and to oscillate from this pre-twist in the direction of closure .

A rim 4 coaxial with the bell 3 surrounds it. It has a bottom 40, an outer cylindrical contour 41 and an inner cylindrical contour 43, from which protrudes inwardly a stop finger 42 which has two opposite faces 47 and 48.

A light 32 which optionally has an enlarged upstream region 32 ₁ provided with a stop 32 ₂ for the end 12 of the spring 1, allows angular displacement of the end region 19 by an angle α ₁ until the face 47 comes into contact with a stopper 37. It is indeed more favorable that this effect of abutment is obtained by the face 47 of the stop finger 42 rather than by the face 18 of the end 12.

This stop bell is formed on a face 37 of a circular sector 35 of the bell 3 which protrudes from its outer cylindrical contour 31. The face 37 may have at least one elastic element 37 '. Another face 38 of the circular sector 35 forms another bell stop whose function will be explained later, and which may have at least one elastic element 38 '.

Spring 1 can be impregnated with grease to reduce friction. Alternatively, a centralizer such as 36 can be housed outside the spring 1 to allow the spring 1 to always work in the same radial position and reduce friction. The centralizer 36 is rotatably connected to the bell 3 for example by a pin or a finger.

A hub 5 is integral in rotation with the assembly consisting of the spring 1 and the bell 3 and, if appropriate, the centering ring 36.

The rim 4 may be a driving element (for example an accessory pulley), the driven element then being the hub 5, or a driven element (for example a crankshaft pulley), the driving element then being the hub 5. In the case of an alternator-starter pulley, in the starting mode of the motor vehicle engine, the hub 5 is driving, and in started mode, it is the rim 4 which is leading.

The operation is as follows: from the rest position (Figure la), a relative speed of the rim 4 higher than that of the hub 5 in the direction of the arrow F which is also the direction of rotation of the engine, in contact with the face 47 of the abutment 42 with the face 17 of the end 12, by driving it in rotation along the lumen 32, which causes the torsion spring 1 in the direction of closure, while the face 17 'remains in contact with the stop 34. This rotary movement can continue until the stop 37 is reached, preferably by the face 47 of the abutment 42 which protrudes laterally from the face 17, which corresponds to a maximum angular amplitude α ₁ ( figure 1c ). The end 12 which circulates in the light 32 disappears behind the circular sector 35.

If instead, the angular velocity of the rim 4 is less than that of the hub 5, then the abutment 42 of the rim 4 can move freely in a circular sector 45 which exists between the outer cylindrical contour 31 of the bell and the cylindrical outline inside 43 of the rim. The circular sector 45 has the shape of a cylinder sector. This counter-rotating movement can continue until the stop 38 is reached by the face 48 of the stop finger 42, which corresponds to a maximum angular amplitude α ₄ ( figure 1c ). It is to increase to the maximum the value of the angle α ₄ that the end 14 of the spring 1 does not exceed (or little) the outer contour 31 of the bell 3 to allow free passage to the finger 42 of the rim 4. It is of course possible to choose α ₄ so that this exceeding of the end 14 does not occur, by providing an additional stop 38 on another circular sector protruding from the outer contour 31 of the bell 3, or, as shown in FIG. Figure 1c, by placing on the rim 4 the additional stop pin 42 'having opposite side faces 47' and 48 '. This stop finger 42 'is spaced from the stop finger 42 by an angular distance chosen as a function of the desired value of α ₄ . This value α ₄ corresponds to the displacement of the stop finger 42 'between the rest position represented in FIG. figure 1c and the coming of the face 48 'abutting on the stop 38 (position represented in dashed lines at the figure 1c ). It is also possible to cancel α ₄ .

The preferred solution ( Figure 1a to 1c ) is however to provide a maximum value of α ₄ to benefit from the rotation of the stop finger 42 in the cylindrical sector 45 and the rim 4. This rotation is performed at constant torque, namely, either at zero torque (residual friction close) or given torque value, providing a friction element, for example between the rim 4 and the hub 5.

The figures 1f and 1g show the characteristics of the pulley described above. To the figure 1f (Null torque), in so-called deceleration mode a zero torque up to α ₄ = 200 °, and in the direction said acceleration, an increasing torque given by the spring 1 to α ₁ = -40 °. Beyond these values, we see the high torque induced by the elastic stops 37 'and 38'. The figure 1g represents the characteristic, when a friction torque is added, which produces a constant shift of the characteristic in a relative direction of rotation as in the other.

• Un mode d'accélération de la jante 4 par rapport au moyeu 5 qui est découplé par le ressort 1 jusqu'à mise en butée en 37 ;
• Un mode de décélération relative de la jante 4 par rapport au moyeu 5, qui est découplé par la rotation à couple constant d'amplitude α₄ du doigt de butée 42 dans le secteur cylindrique 45, jusqu'à mise en butée en 38. On notera que α₄ peut être nul, notamment pour une poulie d'alterno-démarreur.

The variant described above therefore has two modes:

• A mode of acceleration of the rim 4 with respect to the hub 5 which is decoupled by the spring 1 until it stops at 37;
• A relative deceleration mode of the rim 4 with respect to the hub 5, which is decoupled by the constant torque rotation of amplitude α ₄ of the stop finger 42 in the cylindrical sector 45, until abutment 38. note that α ₄ may be zero, in particular for an alternator-starter pulley.

The elastic members 37 'and 38', for example made of elastomer, serve to damp the end-of-stroke abutment.

As the stop finger 42 is arranged so that only its face 47 can come into contact with the end 12 of the spring 1 to control the latter at closure by the side face 17, the operation is irrelevant to the fact that the rim 4 or the hub 5 is the driving element (or the driven element).

The Figures 2a to 2c are relative to another variant in which the stop finger 42 controls the spring 1 to close alternately from one or the other of its ends 12 and 14, which at rest are in abutment at 32 ₂ and 34 .

In this embodiment, from a rest position represented at figure 2a , the bell stop 42 may drive the spring 1 in the closing direction either by its face 47 which comes into contact with the face 17 of the end 12 (as in the previous variant), or by its opposite face 48 which comes into contact with the face 17 'of the end 14 which protrudes from the outer contour 31. The stop finger 42 moves angularly between the faces 17 and 17' of the ends 12 and 14 of the spring 1 which control it at the closing, so that the operation depends only on the relative speed of the rim 4 and the hub 5, whatever the one of these two elements is leading, and is indifferent to the direction of rotation of the pulley.

The spring 1 is driven into closure by its end 12 with a maximum angular stroke α ₁ before coming from the face 47 abutting at 37 (with possibly an elastic member 37 '), or at its end 14 with a maximum angular stroke α ₂ before coming into abutment of its face 48 at 38 (possibly with an elastic element 38 '). The values α ₁ and α ₂ may be equal (α ₁ = α ₂ ) or different (α ₁ ≠ α ₂ ).

The figure 2b represents the stop finger 42 in its four different characteristic positions, namely on the one hand, a rest position in solid lines, on the other hand, in dashed lines, a position of abutment at 37 of its face 47 (stroke angular α ₁ ), then a position of contact between its face 48 and the face 47 'of the end 14 of the spring (stroke α ₃ ), and finally, a position of abutment at 38 of its face 48 (α stroke ₂ ).

Between the ends 12 and 14, there is a maximum angular stroke α ₃ that is best to choose the largest possible. It is also possible to reduce the value of α ₃ , or even to cancel it, for example by adjusting the angular distance between the ends 12 and 14 of the spring 1 (see, for example, the spring shown in FIG. figure 6a ).

The figure 2e shows an embodiment in which the value of the angle α ₃ is reduced due to the presence of an additional stop finger 42 'angularly spaced from the stop finger 42.

In this embodiment, the stop finger 42 moves (arrow F) with an angular amplitude α ₁ between a rest position where it is represented in solid lines and an abutment position (face 47 abuts at 37) represented in FIG. dashed.

During the deceleration of the rim 4 relative to the hub 5, the angular displacement α ₃ of the stop finger 42 is limited by contacting the face 48 'of the stop finger 42' with the face 17 'of the end 14 of the spring 1, after which the stop finger causes its end 48 'end 14 of the spring 1 towards the stop 38, 38', in an angular stroke of maximum value α ₂ .

In other words, the angle α ₃ is limited by the presence of a second stop pin 42 'angularly spaced from the end 14 of the spring 1 to obtain the desired angle α ₃ .

The Figures 2f and 2g show for example characteristics of the pulley of Figures 2a to 2c in the case where the zone of constant torque is at zero torque, that is to say limited to the residual friction ( figure 2f ) or with a given value pair provided by a friction element ( figure 2g ), which produces a constant shift of the characteristic in one direction of rotation as in the other. In this for example, α ₁ = -40 °, α ₂ = 20 ° and α ₃ = 150 ° for the figure 2f , and α ₃ = 50 ° for the figure 2g .

The Figures 3a to 3d represent a variant in which only deflections according to the angles α ₁ and α ₂ are provided (α ₃ = 0) thanks to the implementation of two rim abutments 42 ₁ and 42 ₂ which are in contact in the assembled position with the faces 17 and 17 'of the ends 12 and 14 of the spring 1 ( figure 3a ).

The pulley represented by way of example is an alternator pulley for which the rim 4 is the driving element, thanks to the driving energy provided by the transmission belt 100 and for which the hub 5 is the driven element which drives the alternator (not shown).

• une jante 4 qui présente un fond 40, un contour externe cylindrique 41, un contour interne cylindrique 43, ainsi que deux doigts de butée 41₁ et 42₂ qui sont dans cet exemple diamétralement opposés ; cette jante 4 présente un prolongement cylindrique 6 de plus petit diamètre qui comporte une denture de poulie 61 pour recevoir une courroie striée (courroie automobile de type K) ;
• une cloche 3 dont le contour interne 33 sert à centrer le ressort 1. La cloche présente deux lumières 32 et 32' pour le parcours angulaire des extrémités 12 et 14 du ressort 1 ; les faces 18 et 18' des extrémités 12 et 14 viennent en butée sur les faces respectivement 118, 118' des lumières 32, 32' (figure 3d), et les butées 37 et 38 ne sont pas présentes (cette variante peut être mise en oeuvre pour chacun des modes de réalisation représentés)
• un moyeu 5 présentant une tête pourvue d'une ouverture 52 hexagonale en vue d'un serrage sur l'arbre d'un alternateur, et comportant une région cylindrique centrale 53, et une région cylindrique d'extrémité 54 de plus faible diamètre que la région centrale 53;
• un capot 8, pourvu d'un bouchon 81, qui vient s'emmancher à son pourtour dans un logement de la jante 4 ;
• un ensemble comprenant une pièce d'appui cylindrique 9 et une entretoise 96, la pièce d'appui cylindrique 9 étant emmanchée à force entre la périphérie de la région d'extrémité 54 et le contour interne d'un roulement 62, avec interposition d'une entretoise 96 (avec mise en compression du la rondelle Belleville 92).

According to the sectional view 3b, the perspective view 3c (with removal of the cover 8) and the exploded view of the figure 3d , the pulley comprises:

• a rim 4 which has a bottom 40, a cylindrical outer contour 41, a cylindrical inner contour 43, and two stop fingers 41 ₁ and 42 ₂ which are in this example diametrically opposed; this rim 4 has a cylindrical extension 6 of smaller diameter which comprises a pulley toothing 61 for receiving a ribbed belt (automotive belt type K);
• a bell 3 whose inner contour 33 serves to center the spring 1. The bell has two slots 32 and 32 'for the angular path of the ends 12 and 14 of the spring 1; the faces 18 and 18 'of the ends 12 and 14 abut on the faces 118, 118' respectively of the slots 32, 32 '( figure 3d ), and stops 37 and 38 are not present (this variant can be implemented for each of the embodiments shown)
• a hub 5 having a head provided with a hexagonal opening 52 for clamping on the shaft of an alternator, and having a central cylindrical region 53, and a cylindrical end region 54 of smaller diameter than the central region 53;
• a cover 8, provided with a plug 81, which comes to slip at its periphery in a housing of the rim 4;
• an assembly comprising a cylindrical bearing piece 9 and a spacer 96, the cylindrical bearing piece 9 being force-fitted between the periphery of the end region 54 and the internal contour of a bearing 62, with the interposition of a spacer 96 (with compression of the Belleville washer 92).

The figure 3e illustrates a variant in which a constant friction torque is introduced between the part 9 integral with the alternator shaft (through the successive tightening thereof on the inner contour of a bearing 63 and the hub 5, itself clamped on the inner contour of the bearing 62) and the extension 65 of the rim 4. An assembly comprising a Belleville washer 92, a Washer 93 and a friction washer 94, for example PTFE, is sandwiched (with compression of the Belleville washer 92) between an annular shoulder 91 of the part 9 and an annular shoulder 65 of the extension 61.

The Figures 4a and 4b represent another variant, namely a crankshaft pulley in which only deflections according to the angles α ₁ and α ₂ are provided. The hub 5 is in this case the driving element and the rim 4 is the driven element.

The same is true of Figures 5a to 5g which represent an alternator-starter pulley (ADS), in this case, the rim 4 and the hub 5 are alternately driven and driven depending on whether one is in starter mode or alternator mode. In starter mode, the hub 5 is driving while it is the rim 4 which is driving in alternator mode.

These examples confirm that the concept of the invention depends on the relative rotational movements, but is independent of the driving or driven nature of the rim 4 or the hub 5, and that in the case where the two ends 12 and 14 of the spring 1 are used to control the closing, there is further independence vis-à-vis the direction of rotation of the driving element.

• une jante 4 comportant un contour cylindrique externe 41, et un contour cylindrique interne 43 pourvu de deux doigts de butée 42₁ et 42₂, qui sont dans cet exemple diamétralement opposés ; cette jante présente une région cylindrique principale 6 de plus grand diamètre que le contour externe 41 et qui comporte une denture de poulie 61 pour recevoir une courroie striée (courroie automobile de type K). La jante 4 se prolonge à l'intérieur de la région principale 6 par un prolongement cylindrique 66 ;
• une cloche 3 dont le contour interne 33 sert directement au centrage du ressort 1. Il n'est pas non plus prévu de centreur interne tel que 36. La cloche 3 présente deux lumières 32 pour permettre le parcours angulaire des extrémités 32 et 34 du ressort 1.

The crankshaft pulley shown in Figures 4a and 4b has:

• a rim 4 having an outer cylindrical contour 41, and an inner cylindrical contour 43 provided with two stop fingers 42 ₁ and 42 ₂ , which are in this example diametrically opposed; this rim has a main cylindrical region 6 of larger diameter than the outer contour 41 and which has a pulley toothing 61 for receiving a grooved belt (automotive belt type K). The rim 4 extends inside the main region 6 by a cylindrical extension 66;
• a bell 3 whose inner contour 33 serves directly to center the spring 1. There is also no internal centering device such as 36. The bell 3 has two slots 32 to allow the angular travel of the ends 32 and 34 of the spring 1.

A bearing 62 is housed between the outer contour 364 of a cylindrical extension 362 of the bell 3 and the inner contour 66 'of the cylindrical extension 66.

The inner contour 363 of the extension 362 has a cylindrical shape for example to ensure the passage of a fixing screw for coupling to the crankshaft.

A cover 8 is fitted on the contour 41 of the rim.

At the other end, a flange 110 is mounted centered on the outer contour 364.

Its external cylindrical contour III receives by force-fitting a cylindrical piece 112 of polymeric type and a mass 113, these two parts making it possible, in a known manner, to filter the high frequency vibrations of the crankshaft (damping of the torsional vibrations AVT).

The Figures 5a to 5f concern an alternator-starter pulley (so-called ADS system).

For example, the vehicle engine rotates in the direction of arrow F. At figure 5a , α ₁ then designates the deflection angle due to the electric torque of the alternator (driving rim).

To the figure 5a , α ₂ denotes the deflection angle when the hub 5 is driving (starter mode).

The so-called rest position corresponds to a double contact between the rim and the spring and between the bell and the spring.

The position II corresponds to a contact between the rim 4 and the spring 1 at the maximum angular deflection position α ₁ .

Position III corresponds to a contact between the rim 4 and the spring at the position of maximum angular displacement α ₂ .

The figure 5b (seen from below) shows the belt 100 mounted near the side 105 located on the alternator side (when the pulley is mounted).

The Figures 5c and 5d illustrate the assembly of the pulley. In this embodiment, additional (optional) bell stops 35 ₁ , 37 ₁ , 38 _{1 are provided} , the function of which will be explained below.

This embodiment allows a clearance at angles α ₁ and α ₂ only, the presence of a constant angular torque zone is not desirable in this application.

• une jante 4 comportant un contour cylindrique externe 41, un contour cylindrique interne 43 pourvu de deux doigts de butée 41₁ et 42₂, qui sont dans cet exemple diamétralement opposés ; cette jante 4 présente une région cylindrique 6 de plus petit diamètre que le contour cylindrique 41, et pourvu d'une denture 61 pour recevoir une courroie striée (courroie automobile de type K).
• une cloche 3 dont le contour interne 33 reçoit une bague fendue 36 dont les bords sont désignés par 36₁ et 36₂, et qui présente des lumières se terminant en 36₃ et 36₄ pour le passage des extrémités 12 et 14 du ressort 1 lors de leur rotation. La bague fendue 36 sert au centrage du ressort 1 sur son diamètre extérieur ; sur le pourtour 31 de la cloche 3, sont disposés deux secteurs circulaires 35 et 35₁ pourvus chacun de faces de butées respectivement 37, 38, et 37₁, 38₁, éventuellement pourvus d'éléments amortisseurs respectivement (37', 38'), et (37'₁, 38'₁).
• Un moyeu 5 comportant une collerette 51 pourvue d'une ouverture hexagonale 52 en vue de couplage à l'arbre d'un alternateur et comportant une région cylindrique centrale 53 et une région cylindrique d'extrémité 54 de plus petit diamètre.
• Un palier en deux parties 101, 102 pour assurer la rotation relative entre la jante 4 et le moyeu 5 ; les paliers 101 et 102 sont emmanchés dans la jante 4 pour permettre un guidage en rotation sur la région centrale 53 du moyeu 5.

The alternator-starter pulley has (see Figures 5c and 5d ):

• a rim 4 having an outer cylindrical contour 41, an inner cylindrical contour 43 provided with two stop fingers 41 ₁ and 42 ₂ , which are in this example diametrically opposed; this rim 4 has a cylindrical region 6 of smaller diameter than the cylindrical contour 41, and provided with a toothing 61 for receiving a grooved belt (automotive belt type K).
• a bell 3 whose inner contour 33 receives a split ring 36 whose edges are designated 36 ₁ and 36 ₂ , and which has lights ending in 36 ₃ and 36 ₄ for the passage of the ends 12 and 14 of the spring 1 when of their rotation. The split ring 36 serves to center the spring 1 on its outer diameter; on the circumference 31 of the bell 3 are arranged two circular sectors 35 and 35 ₁ each provided with abutment faces respectively 37, 38, and 37 ₁ , 38 ₁ , optionally provided with damping elements respectively (37 ', 38') , and (37 ' ₁ , 38' ₁ ).
• A hub 5 having a flange 51 provided with a hexagonal opening 52 for coupling to the shaft of an alternator and having a central cylindrical region 53 and a cylindrical end region 54 of smaller diameter.
• A two-part bearing 101, 102 to provide relative rotation between the rim 4 and the hub 5; the bearings 101 and 102 are fitted into the rim 4 to allow rotation guidance on the central region 53 of the hub 5.

The operation will now be described in relation to the figures 5e and 5f.

In a phase where the rim 4 is in acceleration with respect to the hub 5, the end 12 of the spring is driven to closure by its face 17 in contact with the face 47 ₁ of the stop finger 42 ₁ , until the face 47 ₁ comes into abutment at 37, 37 'in the position shown in dashed lines.

The rotation of the rim 4 at the same time drives the stop finger 42 ₂ which disengages from the contact between its face 47 ₂ and the face 17 'of the end 14, until its face 48 ₂ comes into abutment. 38 ₁ as shown in dotted lines. Thus, after an angular movement of amplitude α _1, a double stop effect is obtained at 37 and 38 ₁ with possible damping by the elements 37 'and 38' ₁ .

In the case of an amplitude rotation α ₂ of the driving hub 5, a symmetrical phenomenon occurs.

In fact, the face 47 ₂ of the stop finger 42 ₂ drives, by its face 17 ', the end 14, until the face 47 ₂ comes into abutment at 38 (in the position shown in dotted lines). The stop finger 42 ₁ is then abutted by its face 48 ₁ on the stop 37 ₁ . As before, there is a double thrust effect, with the possible presence of damping elements 38 'and 37' ₁ .

This arrangement which could also be implemented in the other embodiments of the invention is particularly interesting in the particular application that is considered here, because of the significant efforts that transmits a starter-alternator pulley.

The Figures 6a to 6e represent spring variants.

To the figure 6a , the faces 17 and 17 'are positioned on the same plane (or in the vicinity of one another), which has the effect of limiting the radial forces resulting on the bell 3. In this type of embodiment, the stops 42 do not occupy the entire axial length of the bell 3.

To the Figures 6b to 6d , the ends 120 and 140 of the spring 1 are located in the extension of the turns 11, without curved regions and their movement is controlled by closing their faces 170 and 170 'with the stop fingers 142 ₁ and 142 ₂ in the form of corner ( Figures 6c and 6d ) which have plane faces 147 ₁ and 147 ₂ which rest flat on the faces 170 and 170 '.

To the figure 6e , the ends of the spring 1, located in the extension of the turns are not or slightly angularly offset in order to have an integer number of turns.

The Figures 7a to 7c are a variant of the invention in which the end 12 of the spring is housed in an intermediate piece, namely a ring 9 centered with respect to the bell 3 which has the function of reducing the impact of the shocks on the end 12 spring 1 by which it is driven to closure. This ring 9 is thus preferably made of a non-metallic noise-reducing material (for example polyamide or polyurethane) or it has at least one contact face 92, coated with a shock-absorbing material such as an elastomer or a material elastomeric thermoplastic (TPE). This ring 9 makes it possible in particular to fill or complete the function of the above-mentioned elastic elements 37 'or 38' interposed between the faces 47 and 48 and the abutments respectively 37 and 38, which may, however, be implemented in the present variant.

A cylindrical hub 5 provided with a head 51 and a cylindrical region 53, integral in rotation with the bell 3 allows mounting on a shaft, for example an alternator, by its hexagonal opening 52.

The marks 201 and 202 designate bearings interposed between the bell 3 and the rim 4, and 203 a possible friction washer. The rim 4 is for example aluminum or plastic (polyamide, thermosetting resin). The bearings 201 and 202 may be overmolded, as well as the washer 203. A seal 204 seals around a bearing washer 205. The bearing washer 205 optionally has an extension 206 of centering of the bell 3 in an opening 315 of its bottom 313.

The cover 8 provided with a cap 81 is moved to its periphery 82 in the outer contour 41 of the rim 4.

The spring 1 has an axial branch 14 housed in a slot 314 formed in the bell. The radial branch 12 which serves to drive the spring 1 to the closure is housed in a slot 94 of the ring 9 which is formed in an annular sector 91 bordered on both sides by a stop 92 which cooperates with the face 47 of the abutment 42 of the rim 4 to control the spring 1 on closing and with the stop 393 of the bell 3 to then limit the angular displacement of the spring 1 to the angular value α ₁ . The face 47 of the rim abutment thus comes into contact with the abutment 92 of the ring 9 to drive the closing spring and α ₁ is the angle between the face 93 of the ring 9 and the face 393 of the bell 3.

The face 470 'of the rim abutment 420 comes into contact with the abutment 93 of the ring 9. α ₄ is the angle traveled by the face 470' to its contact at 93.

The periphery of the ring 9 and the bell 3 may have at least one other annular sector (95, 395) which makes it possible to split the stops serving to define the angles α ₁ and possibly α ₄ .

The addition of the ring 9 makes it possible to avoid direct contact between the spring 1 and the rim 4 on the one hand, and between the spring 1 and the bell 3 on the other hand, contacts which generate noise by contact metal on metal. In this variant indeed, all the contacts due to the relative movements between the parts take place on the annular part 9, the branches (12, 14) of the spring being housed tightly on the ring 9 and / or on the bell 3. In the case of variants involving angles α ₂ and / or α ₃ , it is possible to implement a second ring 9.

The figures 8 are variants of figures 7a and 7b in which the axial branch 14 is replaced by a branch 144 bent inwards of the spring and which is received in a housing (recess groove 320) of the bell 3. This variant can also be implemented in the case of other embodiments described which do not include a ring 9.

Claims (21)

Decoupling pulley comprising a rim integral with a first power transmission element, and a torsion spring mounted in a receptacle integral with a second power transmission element, one of the power transmission elements being driving and the other of the power transmission elements being conducted, characterized in that the receptacle is a bell inside which is centered the spring, which has a first (12) and a second (14) end region each of which is supported on a support surface (32, 34) of the bell (3), in that the rim has at least one first drive stop (42) having a first face (47) cooperating with the first end region (12) of the spring (1) for driving the latter in the direction of closure in a first direction of relative rotation between the rim (4) and the bell (3), and in that the bell (3) has at least one first stop bell (37, 37 ', 118) whose angular position defines a given first maximum value α ₁ for the displacement of the first end region (12) of the spring (1) driven to closure by said first stop drive (42). Pulley according to claim 1, characterized in that only said first end region (12) of the spring (1) cooperates with said first face (47) with the first drive stop (42), so that the second region end of the spring remains in abutment on its bearing face (34). Pulley according to claim 2, characterized in that , for the second direction of relative rotation between the rim (4) and the bell (3) opposite said first direction of rotation, the periphery of the bell (3) has an angular sector ( 45) at a constant torque for the first drive stop (42) at an angular deflection α ₄ between the first end of the spring (12) and a second stop (38, 38 ', 118'). Pulley according to claim 3, characterized in that the second end region (14) of spring is disengaged from the angular sector (45) to allow the passage of the first drive stop to said second stop (38). , 38 ', 118'). Pulley according to one of claims 1 to 3, characterized in that the second end region (14) of the spring is bent towards the inside of the spring (1) and embedded in a recess groove (320) in the bell (3). Pulley according to claim 1, characterized in that said first end region (12), as well as said second end region (14) cooperating alternately in said relative direction of rotation with said first abutment driving device (42) for driving the spring on closing, and in that the bell has a third bell stop (38, 38 ') whose angular position defines a second maximum given value α ₂ for the deflection of the second end region (14) of the spring (1) driven to closure by a second face (48) of the first drive stop (42) opposite the first face (47). Pulley according to claim 6, characterized in that the bell (3) has an angular sector (45) of free rotation for the first drive stop (42) on an angular displacement α ₃ between the first (12) and the second (14) end of the spring (1). Pulley according to claim 1, characterized in that the spring (1) has a said first end region (12) cooperating with said first face (47 ₁ ) of said first drive stop (42 ₁ ) and a second said end region (14) cooperating with a first face (47 ₂ ) of a second drive stop (42 ₂ ) for driving the spring (1) in the closing direction in a second direction of rotation opposite to the first direction of rotation, and in that the bell (3) has a said third bell stop (38, 38 ', 118') whose angular position defines a second maximum given value α ₂ for the deflection of the second region of end (14) of the spring (1) driven to closure by the second drive stop (14). Pulley according to claim 8, characterized in that the bell has a fourth (38 ₁ , 38 ' ₁ ) and a fifth (37 ₁ , 37' ₁ ) bell stops respectively allowing a said angular displacement α ₁ for the second stop drive (42 ₂ ) when the first end (12) of the spring (1) is driven to closure by the first face (47 ₁ ) of the first drive stop (42 ₁ ) and a said angular deflection α ₂ to the first drive stop (42 ₁ ) when the second end (14) of the spring (1) is driven to closure by the first face (47 ₂ ) of the second drive stop (42 ₂ ). Pulley according to one of Claims 6 to 9, characterized in that α ₁ ≠ α ₂ . Pulley according to one of Claims 6 to 9, characterized in that α ₁ = α ₂ . Pulley according to one of the preceding claims, characterized in that at least one said stopper has a face (37, 38) cooperating with a said face (47, 47 ₁ , 47 ₂ , 48) of a said abutment. drive (42, 42 ₁ , 42 ₂ ) to define a said given maximum value α ₁ and / or α ₂ . Pulley according to one of the preceding claims, characterized in that at least one said abutment stop (37, 38) comprises at least one damping element (37 ', 38'). Pulley according to one of the preceding claims, characterized in that at least one said stopper has a face (118, 118 ') cooperating with a said face (18, 18') of an end region (12, 14 ) of the spring (1) to define a said given maximum value α ₁ and / or α ₂ . Pulley according to one of the preceding claims, characterized in that it comprises a friction element (92, 94) introducing a constant torque between the first and the second power transmission elements. Pulley according to one of the preceding claims, characterized in that the first (12) and / or the second (14) end region is in contact with said bearing face (32, 34). Pulley according to one of claims 1 to 15, characterized in that it comprises an annular piece (9) centered on the bell (3) and which has a housing (94) which receives the first end region (12) of the spring (1), this housing (94) having at least one contact face (92), which is in contact with the said bearing face (392) of the bell. Pulley according to claim 17, characterized in that the annular piece (9) is made of a non-metallic material that dampens impact noise, such as polyamide or polyurethane. Pulley according to claim 17, characterized in that the annular piece has at least one contact face coated with a shock-absorbing material such as an elastomer or an elastomeric thermoplastic material. Pulley according to one of the preceding claims, characterized in that it is an automobile accessory pulley and in that the first power transmission member has a toothing (61) for receiving the teeth of a K-type belt and that the second power transmission member has a coupling member (52) to a said attachment. Pulley according to one of the preceding claims, characterized in that it is a crankshaft pulley and in that the second transmission element comprises a coupling element to a crankshaft, and in that the first power transmission element comprises a toothing. (61) for receiving the teeth of a type K belt.

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